This project is evaluating the pathophysiologic basis of orofacial pain in studies evaluating the effects of prototypic treatments for temporomandibular disorders (TMD). The hypothesized relationship between sleep disorders and muscle pain due to nocturnal muscle hyperactivity was evaluated in a group of subjects participating in a crossover comparison of triazolam, a benzodiazepine hypnotic, and placebo. Subjective rating of sleep quality and quantal measures of sleep were significantly improved by triazolam over the course of four nights but did not have any detectable effects on pain. Muscle hyperacitivity also did not appear to be changed from baseline during the triazolam treatment. These data do not support the clinical utility of benzodiazepine hypnotics for TMD or provide a basis for any hypothesized relationship between sleep and pain attributed to nocturnal hyperactivity. A study currently in progress is evaluating the effectiveness of cognitive behavioral therapy for TMD. Work over the next one-two years will include the evaluation of patients with failed TMJ implants that have resulted in significant pain and dysfunction.